A mounting structure of a current sensor between a battery and a harness is disclosed in, for example, Japanese Patent Application Publication No. 2002-141054, which corresponds to U.S. Pat. No. 6,551,147. The current sensor is mounted on a junction member made of a conductive metallic plate having a rectangle shape. The junction member is disposed between a battery side terminal and a harness side terminal. The battery side terminal is connected to a battery post of a battery. The harness side terminal is connected to a top of a harness. In this structure for mounting the current sensor, the battery side terminal and the harness side terminal can be provided by conventional terminals.
Here, the current sensor is formed in such a manner that a ring shaped detection element is embedded in a resin mold by an insert-molding method. The detection element includes a Hall element and a magnetic field concentration core. A slit is formed in a center of the magnetic field concentration core. By using the slit in the core, the junction member can penetrate through the slit.
However, when the mounting structure includes the magnetic field concentration core, the shape of the current sensor is limited. Accordingly, it is difficult to minimize the dimensions of the mounting structure. Further, the mounting position, i.e., the arrangement of the current sensor is limited. Here, if the mounting structure includes no magnetic field concentration core, the sensitivity of the current sensor is reduced.